The invention relates to a straw-cutting machine for the chopping of stalks, preferably for the chopping of straw behind the straw-walker end of a combine harvester, in accordance with a straw-cutting machine housing (4) in which a rotor (5) provided with cutting tools (7;30) and a drive is pivoted, having a guide plate forming a straw-cutting machine bottom (12) and an outlet (13).
A rotor provided with cutting tools and a drive is pivoted in the straw-cutting machine housing. The cutting tools can be cutters which can be disposed in a fixed position or hung in a floating or free-swinging manner. But rotating catch plates, which can be disposed in a fixed position or hung in a free-swinging manner, can also be used as the cutting tools. The straw-cutting machine housing is generally located behind an inlet funnel whose front wall and rear wall run towards the straw-cutting machine casing and limit the inlet region into the straw-cutting machine housing covered by the rotor. In the region of the rotor, there is furthermore provided a guide plate forming a straw-cutting machine bottom. Furthermore, an outlet exists through which the cut stalks can leave the straw-cutting machine. Above this outlet, an air outlet hood can be disposed. This can be limited towards the inlet funnel and the outlet at its upper and/or lower edge regions by accumulation plates. The accumulation plates preferably extend very closely, that is, for example, up to around 5 to 10 mm, towards the circuit of the cutting tools.
A straw-cutting machine in accordance with the description above is known from DE-OS 195 30 028. In this known straw-cutting machine, the air ring in the form of a mantle enclosing the rotor and rotating with it is broken by the straw guide plate located under the straw-walker end and forming the rear wall of the inlet funnel being curved in an arc-shape in such a manner that the upper curved end lies below the straw-walkers while the lower end tapers off roughly perpendicularly into the inlet of the straw-cutting machine housing.
It is the object of the invention to improve a straw-cutting machine of the type first given.
This object is solved in accordance with the invention by counter-cutters being provided on the straw-cutting machine bottom. The counter-cutters are preferably disposed in a cutter bar. The counter-cutters are preferably located in the outlet region of the straw-cutting machine bottom or of the guide plate, that is in the region of the end of the straw-cutting machine bottom or of the guide plate. The outlet preferably follows on directly from the counter-cutters.
Advantageous embodiments are described below.
Preferably, further counter-cutters are provided in the region of the inlet gap. These counter-cutters are also preferably disposed in a cutter bar. They are preferably located directly behind the inlet gap of the straw-cutting machine. In that the counter-cutters are provided both in the rear region of the straw-cutting machine bottom and in the front region, the straw-cutting effect is substantially enhanced.
Preferably, the counter-cutters protrude into the circuit of the cutting tools. To make this possible, the cutting tools are provided with corresponding slits which are penetrated by the counter-cutters. This is described in U.S. Pat. No. 6,120,373 to which reference is herewith expressly made and whose contentxe2x80x94also in the other aspectsxe2x80x94is herewith incorporated by reference in the present application.
Another advantageous embodiment is characterized in that slots are disposed in the straw-cutting machine bottom. This is described in detail in U.S. Pat. No. 6,126,098 to which reference is herewith expressly made and whose contentxe2x80x94also in the other aspectsxe2x80x94is herewith incorporated by reference in the present application. These slots are preferably provided over the width of the rotor. They have the effect that the ascending air current generated by the narrowing of the rotor""s centrifugal circle and by the counter-cutters is deflected outwards or broken in the inlet region of the straw. In this way, a suction effect is achieved by the rotation of the rotor instead of the ascending air current which impairs the acceptance of the straw. In this way, the acceptance of the straw by the straw-cutting machine is made easier.
Preferably, the slots are penetrated by moving tines. These tines prevent the cut stalks from being able to accumulate in the region of the slots which might impair the slots so that they would lose their venting effect. Instead of the tines, different types of tools can be used which keep the slots free and/or transport the cut stalks on.
The tines are preferably disposed on a drivable roller. They move in the direction of movement of the cut stalks, that is in the direction of the straw-cutting machine, by means of which the cut stalks are transported on to the straw-cutting machine.